This application proposes independent investigator support for a candidate who has been active in the development of non-viral gene delivery since 1986, and has participated in a number of original and significant studies including studies resulting in the conception of polynucleotide vaccines. The scope specifically involves the provision of funds to support the training of the principal investigator over a five year period. The majority of the work is supported by an active ARMDC award which will cover all other costs of the investigation. Recently the candidate has founded and directs a small academic gene therapy program, which has developed methods for mucosal gene delivery and polynucleotide vaccines. This gene therapy program has been assembled at the University of California at Davis, where it has been able to exploit the substantial expertise of the UC Davis CFAR research community and the local primate research center (CRFRC). The candidate currently holds an adjunct appointment, and the requested support would provide for some stability in salary for the candidate, allowing further development as an independent academic investigator. The candidate intends to continue to focus on the development and testing of non-viral gene transfer technologies and the application of those technologies to appropriate clinical targets. The candidate believes that polynucleotide vaccines are ht most appropriate therapeutic application for current non-viral gene delivery technologies, and hence is focused on the development of such vaccines for prevention of lentiviral disease and acute viral pneumonia. Genetic immunization (DNA vaccination) and cytokine augmentation of antiviral immune responses are novel areas of vaccine research. Limited studies have demonstrated that plasmids expressing viral genes induce protective antiviral immune responses after direct injection, and that exogenously administered cytokines can also influence pre-existing or developing host immune responses. However, the efficacy of genetic vaccines (with or without cytokines and /or B7) directed against lentiviruses which cause fatal immunodeficiency in primates (including humans) has not been proven. In addition, wee have yet to clarify immune responses in vaccinated primates that do confer protection versus those that do not. This proposal is aimed at defining a "safe" genetic immunization protocol capable of inducing protective immunity to SIV infection and disease, and concurrently identifying the immune mechanisms responsible for this protective immunity. The identification of these mechanisms is expected to further open the way to effective post exposure immunotherapies for already infected individuals. This application will provide support for achieving the following specific aims; 1. Development of DNA vectors for enhanced expression of lentiviral proteins. 2. Generating and evaluating immune responses to lentiviral proteins after direct DNA injection using mouse and macaque models. 3. Generating and evaluating immune responses to lentiviral proteins after direct DNA injection of vectors expressing both lentiviral proteins and cytokines. 4. Evaluation of clinical course of macaques which have been vaccinated using DNA injection and challenged with pathogenic SIV.